Evaluation of the Role of Matrix Matching for LA-ICP-MS Calibration Approaches in Quantitative Elemental Analysis of Tooth Enamel

A mineral apatite –based calibration approach for Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) was proposed in this work to be used for quantitative multielemental analysis of tooth enamel samples. Tooth enamel is composed mainly of hydroxyapatite therefore natural apatite crystals were expected to fit the matrix. Mineral samples were partially digested and quantitatively analyzed in respect of their bulk, elemental composition by means of ICP-MS/OES. The obtained quantitative data were used to construct the LA-ICP-MS calibration curves based on the apatite crystals for the selected 32 elements. The correlation coefficient values were calculated for each element and varied from none correlation for the most heterogeneous element (Al) to the value above 0.99 (U, REE, etc.), while calibration curve based on 3 selected mineral samples was applied. The usefulness of the proposed calibration approach was evaluated during investigations of elemental composition of tooth enamel and reference materials (NIST 1400, NIST 1486) leading to the promising results.